THE CEPHALOTHOKAX. 



153 



which lie immediately in front of the hindermost, there 

 is a small round aperture for the attachment of the 



Fig. 39. — Astacus fluviatills. — The cephalothoraoio sterna and the endo- 

 phragmal system ( x 2). A, from beneath ; S, from above, a, a', 

 arthrophragms or partitions between the articular cavities for the 

 limbs ; cap, cephalic apodeme ; of, cervical fold ; epn. 1, epimeron of 

 the antennulary somite; h, anterior, and h', posterior horizontal 

 process of endopleurite ; lb, labrum ; m, mesophragm ; mt, meta- 

 stoma ; p, paraphragm ; 1—XIV, cephalothoracic sterna ; 1 — 14, 

 articular cavities of the cephalothoracic appendages. (The anterior 

 cephalic sterna are bent downwards in A so as to bring them into 

 the same plane with the remaining cephalothoracic sterna ; in B 

 these sterna are not shown.) 



